666733987 has 2 divisors, whose sum is σ = 666733988. Its totient is φ = 666733986.

The previous prime is 666733981. The next prime is 666734017. The reversal of 666733987 is 789337666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666733987 - 2¹⁵ = 666701219 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (666733981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333366993 + 333366994.

It is an arithmetic number, because the mean of its divisors is an integer number (333366994).

Almost surely, 2^666733987 is an apocalyptic number.

666733987 is a deficient number, since it is larger than the sum of its proper divisors (1).

666733987 is an equidigital number, since it uses as much as digits as its factorization.

666733987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6858432, while the sum is 55.

The square root of 666733987 is about 25821.1925944562. The cubic root of 666733987 is about 873.6098686106.

The spelling of 666733987 in words is "six hundred sixty-six million, seven hundred thirty-three thousand, nine hundred eighty-seven".